The present invention relates to an energy cable. In particular, the invention relates to a cable for transporting or distributing medium or high voltage electric energy, wherein an extruded covering layer based on a thermoplastic polymer material in admixture with a dielectric liquid is present, enabling, in particular, the use of high operating temperatures together and providing the cable with improved flexibility.
Said cable may be used for both direct current (DC) or alternating current (AC) transmission or distribution.
The requirement for products of high environmental compatibility, composed of materials which, in addition to not being harmful to the environment during production or utilization, may be easily recycled at the end of their life, is now fully accepted in the field of electrical and telecommunications cables.
However the use of materials compatible with the environment is conditioned by the need to limit costs while, for the more common uses, providing a performance equal to or better than that of conventional materials.
In the case of cables for transporting medium and high voltage energy, the various coverings surrounding the conductor commonly consist of polyolefin-based crosslinked polymer, in particular crosslinked polyethylene (XLPE), or elastomeric ethylene/propylene (EPR) or ethylene/propylene/diene (EPDM) copolymers, also crosslinked. The crosslinking, effected after the step of extrusion of the polymeric material onto the conductor, gives the material satisfactory mechanical and electrical properties even under high temperatures both during continuous use and with current overload.
It is well known however that crosslinked materials cannot be recycled, so that manufacturing wastes and covering material of cables at the end of their life may be disposed of only by incineration.